There are known in the prior art dollar bill collectors which make use of the fact that bills such as genuine United States one dollar bills are printed in part with magnetic ink. One such collector is shown and described in Hooker U.S. Pat. No. 3485,358. In the arrangement illustrated in the Hooker patent, in the course of the passage of a bill through the collector and into a collection box, portrait areas of the bill are sensed by a magnetic head to provide a signal indicating that the bill is genuine so that credit can be given. In the event that no signal is produced by the magnetic head as it scans portrait areas of the bill the transport motor of the acceptor is reversed and the bill is returned to the customer. Various attempts have been made by dishonest persons to cheat the dollar bill acceptors to obtain credit or change by inserting a spurious bill in the apparatus. In order to counteract these attempts to cheat the machine various safety features have been incorporated therein. One such safety feature is incorporated in the apparatus shown and described in Okkonen U.S. Pat. No. 3,715,031.
There are also known in the prior art duplicating machines which employ toner particles having magnetic properties to develop a latent image. It is of course desirable that a person who makes a copy of a genuine bill on such a machine not be able to cheat a dollar bill acceptor which at least in part relies on a magnetic test to determine the genuineness of a bill. I have invented an improved paper currency acceptor which will not establish credit in response to the insertion therein of a copy of a genuine dollar bill made on an apparatus employing toner particles having magnetic properties. My apparatus is relatively simple in construction for the result achieved thereby. It is certain in operation.